BEPOET OF THE STATE BOTAOTST. 23 



Spikelets contiguous above, separate below, or all contiguous, 

 sometimes the lower ones compound ; perigynia lanceolate, 

 without a distinct margin, divergent. G-7. 



Spikelets approximate above, separate below, or all contiguous, 

 (capitate in 10) ; perigynia with a distinct margin, widely diver- 

 gent or reflexedat maturity. 8-13. 



f Spikelets staminate at the base, pistillate above. 



Spikelets 3-8, 3-5 flowered, the upper ones approximate or 

 subdistinct, the lowest distinct or remote (capitate in 15), or 

 12-30 flowered and dis])osed in an interrupted spike li'-2^' 

 long, silvery green and shining; perigynia spreading but not 

 refit xed. 14-17. 



Spikelets 3->!, the upper 2 or 3 appro.ximate, separate below, 

 or all contiguous (spikelet single in 18); perigynia slightly con- 

 cave, widely divergent or refiexed at maturity \ plants hright green 

 becoming yello^oish. 18-21. 



Spikelets 3-15 or more, aggregated or ai)pro.\imate, or the upper 

 contiguous and the lower separate (clustered in ;'>1); perig^-nia 

 concave, thin, mostly wide winged-margined, the tips erect or 

 spreading, not refiexed. 22-31. 



t Staminate and pistillate flowers variously situated ; spikelets 

 often wholly sterile or wholly fertile. 32-3-1. 



* Stigmas 3 ; achenium triangular. 



Flowers borne in a short spilce or head, staminate at the apex, 

 pistillate below ; pistillate scales small, caducous, the staminate 

 mostly conspicuous. 35-36. 



Pistillate scales green and leaf-like, persistent, the lowest as 

 long as the spike; perigynia globular, with a long slender beak. 

 37-39. 



B. Staminate and pistillate flowers disposed in separate spikes 

 on the same culm or ])lant (monoecious), or on separate plants 

 (dioecious), the former freciuently androgynous. — Cakex proper. 



* Stigmas 2 (rarely 3) ; achenium lenticular. 



Plant dia'cious. Sterile spike linear, 5' long or less ; fertile 

 spike 3"-5" long, densely flowered ; perigynia oblong, reflexed at 

 maturity. 40. 



Sterile spikes 1-4, stalked or sessile ; fertile spikes 2-5, erect or 

 recurved, sessile or short stalked, densely or subdensely flowered ; 

 perigynia with a short point or pointless ; scales blackish-prwple 

 or reddishhroion, not atoned. 41-46. 



